As an example of a vehicle brake device configured to control a braking force applied to a vehicle depending on an amount of brake operation due to a driver, for example, a vehicle brake device disclosed in JP-A-2008-87617 (Patent Document 1) has been known. In the vehicle brake device, an input piston and a pressing piston are held at a separated state with a predetermined interval (a stroke), and thus the braking force based on a control oil pressure generated by an accumulator and a linear valve is applied to a wheel cylinder depending on the movement of the input piston. In the vehicle brake device disclosed in Patent Document 1, it is possible to detect a malfunction of a master cut valve by stepping a brake pedal.
However, the prior device disclosed in Patent Document 1 has a configuration in which, if the brake pedal is not stepped, the malfunction of the master cut valve cannot be detected, and thus the failure of the master system cannot be detected. In this configuration, the malfunction cannot be detected without the cooperation of a driver.